Lithographic ink composition



Patented May 8, 1934 UNITED STATES 7i OFFICE John V. Mehl,

Union City, N. J.

No Drawing. Application August 16, 1932, Serial No. 629,082

1 Claim.

This invention relates to improvements in lithographic ink compositions and has for an object the provision of an improved lithographic ink which eliminates the necessity for wetting the 5 lithographic plate between each printing operation.

A further object of this invention is the provision of an improved lithographic ink which may easily be applied to the prepared plate and which will only adhere to the desired portions of the plate so that a sharply defined print may be made by the plate.

In the lithographing art the piate, consisting of a flat stone, or a zinc or aluminum sheet, has the design formed thereon by coating or impregnating the surface of the plate with a greasy or waxy material, by which such portion of the plate is made repellent to water but with an affinity for greasy or waxy ink, while the remaining portions of the surface of the plate will take on a thin layer of water which will then repel greasy or waxy ink.

Various methods are used in applying the design to the surface of a plate, such as by drawing in reverse directly on the surface of the plate by hand with a greasy or waxy crayon, or by pen or brush, with liquid greasy ink, or by transferring the same from paper or from engraved plates or woodcuts, or from photographic plates upon -which the design has been formed by a coating of greasy or waxy material. Whichever method is used to form the subject matter upon the plate, the principle of the art of printing from lithographic plates is the same, which is the chemical affinity of the greasy or waxy material coated or impregnated in the plate, for substances of the same nature in the ink, and the repugnance of such substances for water, by which the design on the plate will repel a coating of water but will take -.a coating of the ink, and the uncoated portions of the plate will take a coating of water, which will prevent the ink from adhering to such watercoated portions.

The method now in use for printing from lithbgraph-plates requires the prepared plate to be first coated with a film of water, which adheres to the portions of the plate free from the greasy material forming the designs thereon, and secondly, applying a coating of greasy ink to the plate, ,which will adhere to and cover the design on the plate but will be repelled by the water coating. A sheet of paper or other flexible material then being placed upon the plate will take up the greasy ink from the design thereon, thus producing a ,print of the design upon the paper. Such method (Cl. i3435) requires the repetition of a water coating and an ink coating successively applied to the plate for each printing.

Still another object of the invention is the provision of a lithographic ink consisting of a material having an afiinity for greasy substances, and other material repellent to greasy substances. These objects are accomplished by incorporating in the usual greasy lithographic ink a grease-repellent liquid consisting of a solution of sodium hyposulfite, glycerine, rubber cement, and nicotine, and forming an emulsion of the said liquid with the ink. The most important of these ingredients is the sodium hyposulfite, which holds the liquid on the surface of the ink, and the nicotine which is a repellent to the greasy substance in the ink will be deposited upon the portions of the plate not covered by the coating forming the design. The glycerine prevents drying of the solution in the ink, and the rubber cement renders the solution tacky and prevents piling of the ink upon the plate.

While the proportions of these substances may be varied, the most satisfactory results are accomplished by the following proportions by weight: With one pound of the usual greasy lithographic ink is mixedone-half ounce of a saturated solution of sodium hyposulfite, one-half ounce of glycerine, one-half ounce of rubber cement, and one-half ounce of nicotine in solution with one-quarter ounce of benzol as a vehicle to produce an emulsion with the ink. The aforesaid substances are thoroughly mixed, forming a jellylike solution which is then worked in with the ink to form minute globules of the ink interspersed with minute globules of the solution. While the solution is dificult to combine with the ink, the addition of a small quantity of benzol readily permits an emulsion being formed with the ink; the benzol being volatile, evaporates from the solution as the same is worked in with the ink.

The ink thus prepared may be applied to the lithographic plate in the usual manner by means of a roller, which, passing over the plate, will deposit a thin film of the greasy ink upon the design formed on the plate, and on the remaining portions of the plate the solution separating from the ink will be deposited, thus producing in one operation what has heretofore been accomplished in two operations, namely, the wetting of the plate, followed by the inking of the plate. After the plate has been inked with the improved material the paper, leather or other flexible material may be applied to the surface of the plate and the inked coating on the plate in the form Ill) rated therein the substance having an affinity for the uncoated portions of the plate.

What is claimed is:

A lithographic ink consisting of an emulsion of a greasy ink, a saturated solution of sodium hyposulfite, glycerine, rubber cement, and nicotine in the proportion of substantially one pound of the greasy ink to one-half ounce of each of the other substances.

JOHN V. MEI-IL. 

